Chemical Constituents of Pteris fauriei

Abstract

The group of ferns from the genus Pteris (Pteridaceae) contains 300 cosmopolitan species, with 66 species being endemic to China [1]. Several plants in the genus are widely used in traditional Chinese medicine for relieving internal heat or fever, swelling and diarrhea, and removing toxicity [2, 3]. Previously, phytochemical investigations on the Pteris genus had led to the isolation of various phenolic compounds, flavonol glycosides, kauranes, and pterosin sesquiterpenes [4–8]. Some extracts and compounds of plants in the genus showed various bioactivities such as antitumor, antibacterial, cytotoxic, and free radical-scavenging activities [9–11]. P. fauriei Hieron. is distributed in North Vietnam, Japan, and southern China. There have been no reports on the isolation of compounds from it. During the search for bioactive compounds from medicinal plants in Yunnan of China, we investigated the plant. P. fauriei was collected from Kunming of Yunnan, China in April, 2006. The air-dried whole plants (0.8 kg) were chopped and exhaustively extracted with 95% EtOH. Water (1.5 L) was added to the EtOH extract (100 g), and the resulting solution was extracted with petroleum ether and EtOAc successively (four times, each 0.8 L). The EtOAc extract (27 g) was separated on a silica gel column and eluted with petroleum ether containing increasing amounts of EtOAc to obtain nine fractions. Fraction B (4.2 g) was subjected to repeated column chromatography (silica gel, petroleum ether–EtOAc, 20:1) to afford 6 (47 mg). Fraction C (7.1 g) was isolated on a Sephadex LH-20 column (CHCl3–MeOH, 3:2) to give 5 (13 mg). Fraction D (1.3 g) was chromatographed over preparative TLC (petroleum ether–EtOAc, 3:1) to furnish 1 (8 mg). Fraction E (1.8 g) was purified on a Sephadex LH-20 column (MeOH) to obtain 2 (3 mg) and 3 (4 mg). Fraction F (1.5 g) was subjected to Sephadex LH-20 column chromatography (MeOH) to afford 4 (15 mg). Fraction G (4.7 g) was chromatographed over silica gel (CHCl3–Me2CO, 20:1) and then purified by chromatography over Sephadex LH-20 (MeOH–H2O, 9:1) to furnish 7 (43 mg). Fraction H (5.2 g) was isolated on MCI gel and eluted with a gradient of 0–100% MeOH in H2O to obtain 8 (16 mg). Aristolone (1), C15H22O, colorless amorphous powder. The mass spectrum exhibited peaks for ions at m/z 218 (M+, 43), 203, 191, 177, 161, 147, 91. PMR spectrum (CDCl3, , ppm, J/Hz): 1.19, 1.20, 1.30 (each 3H, s), 1.06 (3H, d, J = 6.7), 5.75 (1H, s). 13C NMR and DEPT spectra (CDCl3, , ppm): 196.6, 167.9, 124.7, 40.0, 39.6, 39.1, 35.9, 33.5, 31.0, 30.1, 26.5, 24.7, 22.9, 16.9 and 16.6 [12]. Kaempferol (2), C15H10O6, yellow amorphous powder 13 . Luteolin (3), C15H10O6, yellow amorphous powder [14].